Oil pan structure and an engine therewith

Abstract

An oil pan structure includes a plurality of reinforcement beads of several kinds. An engine utilizes the oil pan, whereby the strength and vibration-rigidity (rigidity against vibration) of the oil pan and the engine are sufficiently enhanced so that a natural frequency of the oil pan and the engine therewith becomes adjustable through a selection as to the numbers, locations, and sizes of the beads.

1. An oil pan structure for an engine, the oil pan structure comprising:
 an oil pan flange for being fastened with bolts to an undersurface of an engine crankcase; 
 a bottom wall that forms a bottom part of an engine; 
 a left side wall and a right side wall extending in a longitudinal direction of the engine, 
 a front side wall and a rear side wall extending in a transverse direction of the engine, 
 wherein each of the left side wall, the right side wall, the front side wall, and the rear side wall extends between an edge of the bottom wall and the oil pan flange such that the oil pan structure defines an internal space and is capable of storing engine-internal oil that is stirred in the internal space, 
 wherein each of the bottom wall, the left side wall, the right side wall, the front side wall, and the rear side wall comprises a plurality of reinforcement beads which swell at a middle part thereof with a corrugation shape toward the internal space of the oil pan structure, 
 wherein the reinforcement beads extend from the bottom wall toward the left or right side wall, or from the bottom wall toward the front or rear side wall, and 
 wherein the reinforcement beads are substantially U-shaped beads which each comprise a closed end, a tunnel-shaped part, and an open end, the tunnel-shaped part being disposed at a middle part of the reinforcement bead and swelling toward the internal space of the oil pan structure, and the closed end forming a smooth transition between the tunnel-shaped part of the reinforcement bead and a surface of the oil pan structure. 
 
     
     
       2. An engine comprising the oil pan structure of  claim 1 . 
     
     
       3. An engine comprising:
 a crankcase; and 
 the oil pan structure of  claim 1  fastened to an undersurface of the crankcase. 
 
     
     
       4. The engine of  claim 3 , wherein a length of the tunnel-shaped parts of the reinforcement beads is set such that the natural frequency of the oil pan structure is different than a resonance frequency of the engine. 
     
     
       5. The oil pan structure according to  claim 1 , wherein the internal space is substantially box-shaped. 
     
     
       6. The oil pan structure according to  claim 1 , wherein a length of the tunnel-shaped parts of the reinforcement beads is set such that the natural frequency of the oil pan structure is different than a resonance frequency of the engine. 
     
     
       7. The oil pan structure according to  claim 1 , wherein a drain hole is provided in the bottom wall, and a drain cock is fitted to the drain hole as a reinforcement element for the bottom wall. 
     
     
       8. An oil pan structure for an engine, the oil pan structure comprising:
 an oil pan flange for being fastened with bolts to an undersurface of an engine crankcase; 
 a bottom wall that forms a bottom part of an engine; 
 a left side wall and a right side wall extending in a longitudinal direction of the engine, 
 a front side wall and a rear side wall extending in a transverse direction of the engine, 
 wherein each of the left side wall, the right side wall, the front side wall, and the rear side wall extends between an edge of the bottom wall and the oil pan flange such that the oil pan structure defines an internal space and is capable of storing engine-internal oil that is stirred in the internal space, 
 wherein each of the bottom wall, the left side wall, the right side wall, the front side wall, and the rear side wall comprises a plurality of reinforcement beads which swell at a middle part thereof with a corrugation shape toward the internal space of the oil pan structure, 
 wherein the reinforcement beads extend from the bottom wall toward the left or right side wall, or from the bottom wall toward the front or rear side wall, 
 wherein the reinforcement beads each comprise a first end-opening, a tunnel-shaped part, and a second end-opening, the tunnel-shaped part being disposed at a middle part of the reinforcement bead and swelling toward the internal space of the oil pan structure, and the first and second end-openings being smaller in width than the tunnel-shaped part. 
 
     
     
       9. An engine comprising the oil pan structure of  claim 8 . 
     
     
       10. An engine comprising:
 a crankcase; and 
 the oil pan structure of  claim 8  fastened to an undersurface of the crankcase. 
 
     
     
       11. The engine of  claim 10 , wherein a length of the tunnel-shaped parts of the reinforcement beads is set such that the natural frequency of the oil pan structure is different than a resonance frequency of the engine. 
     
     
       12. The oil pan structure according to  claim 8 , wherein the internal space is substantially box-shaped. 
     
     
       13. The oil pan structure according to  claim 8 , wherein a length of the tunnel-shaped parts of the reinforcement beads is set such that the natural frequency of the oil pan structure is different than a resonance frequency of the engine. 
     
     
       14. The oil pan structure according to  claim 8 , wherein a drain hole is provided in the bottom wall, and a drain cock is fitted to the drain hole as a reinforcement element for the bottom wall. 
     
     
       15. An oil pan structure for an engine, the oil pan structure comprising:
 an oil pan flange for being fastened with bolts to an undersurface of an engine crankcase; 
 a bottom wall that forms a bottom part of an engine; 
 a left side wall and a right side wall extending in a longitudinal direction of the engine, 
 a front side wall and a rear side wall extending in a transverse direction of the engine, 
 wherein each of the left side wall, the right side wall, the front side wall, and the rear side wall extends between an edge of the bottom wall and the oil pan flange such that the oil pan structure defines an internal space and is capable of storing engine-internal oil that is stirred in the internal space, 
 wherein each of the bottom wall, the left side wall, the right side wall, the front side wall, and the rear side wall comprises a plurality of reinforcement beads which swell at a middle part thereof with a corrugation shape toward the internal space of the oil pan structure, 
 wherein the reinforcement beads extend from the bottom wall toward the left or right side wall, or from the bottom wall toward the front or rear side wall, and 
 wherein a plurality of substantially triangular wave-grooves are disposed on the left side wall and the right side wall of the oil pan structure and extend in the longitudinal direction, 
 wherein a distance between the left side wall and the right side wall increases in a direction from the bottom wall toward the oil pan flange, 
 wherein the left side wall and the right side wall are connected by the bottom wall, and 
 wherein the cross section of the substantially triangular wave-grooves forms a zigzag shape. 
 
     
     
       16. An engine comprising the oil pan structure of  claim 15 . 
     
     
       17. An engine comprising:
 a crankcase; and 
 the oil pan structure of  claim 15  fastened to an undersurface of the crankcase. 
 
     
     
       18. The engine of  claim 17 , wherein a length of tunnel-shaped parts of the reinforcement beads is set such that the natural frequency of the oil pan structure is different than a resonance frequency of the engine. 
     
     
       19. The oil pan structure according to  claim 15 , wherein the internal space is substantially box-shaped. 
     
     
       20. The oil pan structure according to  claim 15 , wherein a drain hole is provided in the bottom wall, and a drain cock is fitted to the drain hole as a reinforcement element for the bottom wall.